Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
Development. 2020 Jul 8;147(13):dev188912. doi: 10.1242/dev.188912.
In many flowering plants, asymmetric division of the zygote generates apical and basal cells with different fates. In , the apical cell generates the embryo while the basal cell divides anticlinally, leading to a suspensor of six to nine cells that remain extra-embryonic and eventually senesce. In some genetic backgrounds, or upon ablation of the embryo, suspensor cells can undergo periclinal cell divisions and eventually form a second twin embryo. Likewise, embryogenesis can be induced from somatic cells by various genes, but the relationship with suspensor-derived embryos is unclear. Here, we addressed the nature of the suspensor to embryo fate transformation and its genetic triggers. We expressed most known embryogenesis-inducing genes specifically in suspensor cells. We next analyzed morphology and fate-marker expression in embryos in which suspensor division was activated by different triggers to address the developmental paths towards reprogramming. Our results show that reprogramming of suspensor cells towards embryonic identity is a specific cellular response that is triggered by defined regulators, follows a conserved developmental trajectory and shares similarity to the process of somatic embryogenesis from post-embryonic tissues.
在许多开花植物中，合子的不对称分裂产生具有不同命运的顶端和基细胞。在拟南芥中，顶端细胞产生胚胎，而基细胞进行斜向分裂，导致六个到九个细胞的悬浮体保持胚胎外，并最终衰老。在某些遗传背景下，或在胚胎缺失的情况下，悬浮体细胞可以进行平周细胞分裂，并最终形成第二个双胞胎胚胎。同样，通过各种基因可以从体细胞诱导胚胎发生，但与悬浮体衍生胚胎的关系尚不清楚。在这里，我们研究了悬浮体向胚胎命运转变及其遗传触发因素的本质。我们专门在悬浮体细胞中表达了大多数已知的诱导胚胎发生的基因。接下来，我们分析了不同触发因素激活悬浮体分裂后胚胎的形态和命运标记表达，以解决重编程的发育途径问题。我们的结果表明，悬浮体细胞向胚胎身份的重编程是一种特定的细胞反应，由特定的调节剂触发，遵循保守的发育轨迹，与来自胚胎后组织的体细胞胚胎发生过程具有相似性。
